Thrombelastography changes in pre-eclampsia and eclampsia.

We have measured platelet count, bleeding time and thrombelastography (TEG) variables and the correlation between these variables in 49 pregnant patients presenting with pre-eclampsia or eclampsia. Eighteen patients (37%) had a platelet count < or = 150 x 10(9) litre-1 and seven (14%) had a platelet count < or = 100 x 10(9) litre-1. Bleeding time was prolonged > 9.5 min in 13 (27%) patients and the TEG was abnormal in four (8%). The TEG variables, k time and maximum amplitude (MA) had a strong correlation with platelet count (k time-platelet count < or = 150 x 10(9) litre-1, r = -0.68, P = 0.003, platelet count < or = 100 x 10(9) litre-1, r = -0.84, P = 0.02; MA--platelet count < or = 150 x 10(9) litre-1, r = 0.72, P = 0.001, platelet count < or = 100 x 10(9) litre-1, r = 0.78, P = 0.04). There was no correlation between bleeding time and thrombocytopenia (platelet count < or = 150 x 10(9) litre-1, r = -0.18, ns; platelet count < or = 100 x 10(9) litre-1, r = 0.09, ns). There was no correlation between bleeding time and any measured TEG variable. Of the 10 (20%) patients with an adequate platelet count (> 100 x 10(9) litre-1) but prolonged bleeding time, the TEG was normal, suggesting adequate haemostasis. An MA of 53 mm, which is the lower limit for normal pregnancy, correlated with a platelet count of 54 x 10(9) litre-1 (95% confidence limits 40-75 x 10(9) litre-1). Although the number of patients with severe thrombocytopenia was small, a platelet count of 75 x 10(9) litre-1 should be associated with adequate haemostasis.